DESCRIPTION: The project is based on the hypothesis that immunotherapy is a more potent treatment than intranasal steroids for allergic rhinitis because it can more profoundly alter the immune system and reach sites beyond the nose. A double blind, placebo-controlled study is proposed. The effects of immunotherapy and intranasal steroids on the nasal response to allergen will be compared by studying mast cell activation and distribution, cellular inflammation, and allergen-induced hyperresponsiveness. In addition, immunotherapy will be compared with intranasal steroids with regard to controlling all the symptoms of allergic rhinitis such as eye irritation and sinus and pulmonary problems. The candidate will also test the hypothesis that immunotherapy alters the T cell response of the nasal mucosa to allergen from the Th2 to the Th1 profile.